Composite bulletproof window panel

ABSTRACT

A bulletproof composite window panel has two outer glass panes with two inner plastic panes being located between the glass panes, each pane being spaced from but parallel to its neighboring panels. Tubular spacing members of substantially semicircular cross section are located between juxtaposed circumferentially extending marginal portions of the respective panels to prevent the panels from contacting each other, and sealing means seals the spaces between the panels along the circumferentially extending marginal portions.

United States Patent [72] inventor Alfred Arnold Alfred-Klingelestr. 7064, Geradstetten, Germany [21] Appl. No. 819,405 [22] Filed Apr. 25, 1969 [45] Patented Dec. 28, 1971 [32] Priority May 17, 1968 3 3 Austria 3 1 A 4766/68 [54] COMPOSITE BULLETPROOF WINDOW PANEL 8 Claims, 2 Drawing Figs.

152] US. Cl 161/45, 52/616, 89/36 R, 156/109, 161/404, 109/80 {5 1 1 Int. Cl E04c 2/23, E04b 2/28, F41h 5/00 50] Field of Search 161/40, 45, 183, 192, 404; 156/109; 109/78, 80; 52/616; 89/36 R [5 6] References Cited UNITED STATES PATENTS 1,988,964 1/1935 Barrows 161/45 2,741,809 4/1956 Englehart et a] 161/45 X 3,135,645 6/1964 Burkley et al 161/404 X 3,179,553 4/1965 Franklin 161/404 X 3,388,034 6/1968 McCombie 161/183 3,406,086 10/1968 Foster 161/183 3,431,818 3/1969 King 161/404 X FOREIGN PATENTS 289,551 3/1965 Netherlands 52/616 Primary Examiner.lohn T. Goolkasian Assistant Examiner-Joseph C. Gil Attorney-Michael S. Striker COMPOSITE BULLETIROOF WINDOW PANEL BACKGROUND OF THE INVENTION The present invention relates generally to a composite panel, and more particularly to a bulletproof composite window panel.

Bulletproof window panels are already known, as is the fact that they can be made as composite panels consisting of a plurality of individual panes. In one such construction at least one light-transmissive, that is opaque or transparent panel of synthetic plastic material such as high-molecular thermoplastic polycarbonate on the basis of aromatic dihydroxide compounds, preferably bisphenylolalkanes, having a thickness of at least 2 mm. is sandwiched between two glass panels. The 1 three panels are then so connected with one another they have limited freedom of sliding movement relative to one another. It is preferred to connect the panels with a binder which remains soft, such as silicone rubber.

However, it has been found that the synthetic plastic panel must be relatively thick-that is, it must have a thickness on the order of 25 mm.if the composite panel is to be bulletproof. This is evidently a disadvantage, as is the fact that even the use of binders between the panels is not always able to prevent the development of undesirable optical faults in the compmite panel, such as Newtons rings.

SUMMARY OF THE INVENTION It is, accordingly an object of the present invention to overcome these disadvantages.

More particularly it is an object of the present invention to provide a composite panel, particularly a window panel, which is bulletproof and at the same time simple and inexpensive to manufacture.

An additional object of the invention is to provide such a composite panel which is low in weight and which does not interfere with visibility therethrough and does not have optical faults.

in pursuance of the above objects, and others which will become apparent hereafter, one feature of my invention resides in the provision of a composite panel, particularly a bulletproof window panel, which includes a pair of coextensive first panels of a first material arranged in two spaced parallel first planes, and at least one additional second panel of a different second material coextensive with the first panels and arranged in a second plane intermediate to the first planes with spacing from both of the first panels.

Spacing means is interposed between juxtaposed circumferentially extending marginal portions of the respective panels for maintaining the latter out of contact, and sealing means extends along and in contact with these marginal portions for the purpose of sealing the spaces between the respective panels.

It is advantageous that the first or outer panels be of glass, whereas the inner or second panel be of synthetic plastic material. However, this should not be considered to be a limiting requirement, only a preferred construction. It will also be appreciated that two or more inner panels of synthetic plastic material may be used. If two inner panels of synthetic plastic material are employed, it is sufiicient if they each have a thickness of 5 mm.

The fact that each panel is spaced slightly from the panels located at its opposite sides makes it possible for each panel to undergo a slight deformation on impact of a missile, such as a bullet, and this in turn increases significantly the penetration resistance of the novel composite panel according to the present invention.

The ability to perform yielding movements in response to impact of a missile is further enhanced by the fact that the individual panels are connected together only at their circumferential marginal portions and that, in accordance with a further feature of the invention, the spacing means which is located between the circumferential marginal portions of juxtaposed panels, engages these marginal portions only with linear contact, or at least with substantially linear contact rather than area contact.

Additionally the sealing means I use is elastic and these measures taken together avoid the development of stresses in the composite panel,.which could result from the fact'that the coefficient of expansion of the synthetic plastic material is a multiple of that of the glass, for instance on the order of eight times the coefficient of expansion of glass.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a plan view of a composite panel according to the present invention; and

FIG. 2 is a fragmentary section through the panel of FIG. I, on an enlarged scale.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing now the two figures in detail it will be seen that l have shown my illustrated panel in HO. 1 to be of rectangular outline. Of course, it can have any outline desired.

As shown in FIG. 2 my panel is composed in the particular embodiment illustrated of two outer or first panels 1 and 2 which consist of glass, and of two inner or second panels 3 and 4 which consist of synthetic plastic material. The synthetic plastic material of the panels 3 and 4 is preferably a polycarbonate.

Each of the panels 1, 2, 3 and 4 is spaced from its neighboring panels to provide a free space 10 between adjacent ones of the panels. This spacing is provided and maintained by the spacing means 5 which preferably, although not necessarily, is configurated in form of elongated tubular members 5, such as drawn aluminum tubes, which in the illustrated embodiment are of substantially semicircular cross section and are located inwardly of the outer edges of the respective panels intermediate the juxtaposed circumferentially extending marginal portions thereof. The spacing means 5 constitutes a closed frame 6 located, as already pointed out, slightly inwardly'of the outer edges of the respective panels 1-4. It will be seen that the spacing means 5 engages the juxtaposed circumferentially extending marginal edge portions of the respective panels which it spaces, only with a linear or substantially linear contact. The space remaining between the juxtaposed marginal portions of adjacent panels spaced by the spacing means, that is the space which is open in outward direction of the composite panel, is filled with sealing means of suitable type, which in accordance with the present invention is preferably an elastic sealing material 8 which remains elastic at all times, such as silicon rubber. The presence of the spacing means 5, whose line contact with the marginal portions of the respective panels is identified with reference numeral 9 by way of illustration, and the sealing means 8 together seal the spaces 10 between the adjacent panels so that no moisture-containing air can enter into these spaces. At the same time the sealing means 8 provides for a tight connection between adjacent panels.

It will be appreciated that during manufacture the spaces 10 have in known manner a dry gas circulated therethrough to remove any moisture that may be contained in the spaces 10-, and to prevent the intrusion of moisture thereinto until the spaces 10 can be sealed.

It will be understood that the semicircular cross-sectional configuration of the spacing means 5 is not the only configurabetween which it is located, and the sealing means 8 can penetrate into these wedge-shaped spaces and provide for particularly good connection between the panels. In addition, the flat surface on each of the spacing means 5, facing the interior of the respective spaces 10, provides for a pleasing appearance.

Panels according to my present invention are not only light in weight, but are also simple in construction and therefore relatively inexpensive. Furthermore, their thickness overall is comparatively small while the panels are yet bulletproof. In addition to this, they are and remain clear, that is they are not possessed of optical faults and visibility through these panels cannot be detrimentally influenced, for instance by moisturecontaining air penetrating into the spaces 10. Panels of this type can be used in a great variety of different applications, for instances as partitions in taxicabs between the passengers and the driver to protect the latter from attack, in financial institutions between the teller and the customers, for display windows in jewelry stores, and in similar applications.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.

While the invention has been illustrated and described as embodied in a bulletproof composite window panel, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from he spirit of the present invention.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. A composite panel, particularly a bulletproof window panel, comprising a pair of coextensive first panels of transparent material arranged in two spaced parallel first planes; at least one second panel of yieldably deflectable light-transmissive polycarbonate material coextensive with said first panels and arranged in a second plane intermediate said first planes, said second panel having a thickness of at least 2 millimeters and being spaced from said first panels by a distance sufficient for each of said panels to undergo a slight deformation on receiving an impact; spacing means interposed between juxtaposed circumferentially extending marginal portions of the respective panels for maintaining the latter spaced at said distance; and sealing means extending along and in contact with said marginal portions for sealing the space between the respective panels.

2. A composite panel as defined in claim 1, wherein said first material is glass.

3. A composite panel as defined in claim 2, wherein said sealing means is resiliently yieldable.

4. A composite panel as defined in claim 2, wherein said spacing means comprises elongated spacing members constructed so as to engage the respective juxtaposed marginal portions with at least substantial line contact.

5. A composite panel as defined in claim 2, wherein said spacing means comprises elongated tubular spacing members of substantially semicircular cross-sectional configuration.

6. A composite panel as defined in claim 5, wherein said spacing members together constitute circumferentially complete annular spacing elements each interposed between said juxtaposed circumferentially extending marginal portions of respectively adjacent ones of said panels.

7. A composite panel as defined in claim 1; further comprising at least one additional section panel interposed with spacing between the first-mentioned second panel and one of said first panels, parallel to and coextensive with both; said spacing means also being interposed between juxtaposed circumferentially extending marginal portions of said additional second panel and said first-mentioned second panel and one first panel, respectively; and said sealing means also sealing the spaces between said additional second panel and said firstmentioned second panel and one first panel, respectively.

8. A composite panel as defined in claim 7, said additional second panel also being of poly arbon ate material. 

2. A composite panel as defined in claim 1, wherein said first material is glass.
 3. A composite panel as defined in claim 2, wherein said sealing means is resiliently yieldable.
 4. A composite panel as defined in claim 2, wherein said spacinG means comprises elongated spacing members constructed so as to engage the respective juxtaposed marginal portions with at least substantial line contact.
 5. A composite panel as defined in claim 2, wherein said spacing means comprises elongated tubular spacing members of substantially semicircular cross-sectional configuration.
 6. A composite panel as defined in claim 5, wherein said spacing members together constitute circumferentially complete annular spacing elements each interposed between said juxtaposed circumferentially extending marginal portions of respectively adjacent ones of said panels.
 7. A composite panel as defined in claim 1; further comprising at least one additional second panel interposed with spacing between the first-mentioned second panel and one of said first panels, parallel to and coextensive with both; said spacing means also being interposed between juxtaposed circumferentially extending marginal portions of said additional second panel and said first-mentioned second panel and one first panel, respectively; and said sealing means also sealing the spaces between said additional second panel and said first-mentioned second panel and one first panel, respectively.
 8. A composite panel as defined in claim 7, said additional second panel also being of polycarbonate material. 